Patent EA-000590-B1 (EA)
Title: Isolation tool
Inventor: DYCK JOHN
IPC: F16L55/132
Filed: 1997-01-28
Abstract: 1. A braking apparatus for locking a pipeline isolation tool used to plug a pipeline at a predetermined location against the pressure of fluid in said pipeline, said tool including a housing adapted for movement through said pipeline and for supporting said braking apparatus, comprising: a plurality of gripping means disposed about said housing for frictionally engaging an inner surface of said pipeline to lock said tool in a predetermined location in said pipeline; support means to independently support at least respective ones of said gripping means so that first and second portions of said gripping means are axially spaced apart in the longitudinal direction of said housing; setting means actuatable for moving said support means between a first position wherein said gripping means are disengaged from said inner surface and a second position in which said gripping means engage said surface for locking of said tool in said predetermined location; and drive means for actuation 'of said setting means for selective movement of said gripping means between said first and second positions thereof. 2. A pipeline isolation tool for plugging a pipeline at a predetermined location, comprising: housing means adapted for movement through said pipeline, said housing having first and second ends; sealing means comprising at least first and second resilient sealing members disposed annularly about said housing, said first and second members being axially spaced apart in the longitudinal direction of said housing and being radially expandable into fluid sealing contact with an inner surface of said pipeline; seal expanding means selectively actuatable to radially expand said sealing members into fluid sealing contact with said inner surface; braking means for locking said tool in said predetermined location, said braking means including a plurality of gripping means disposed about said housing for frictionally engaging said inner surface to lock said tool in said predetermined location, support means to independently support at least respective ones of said gripping means so that first and second sub groupings of said gripping means are axially spaced apart in the longitudinal direction of said housing and setting means actuatable for moving said support means between a first position wherein said gripping means are disengaged from said inner surface and a second position in which said gripping means engage said surface for locking of said Cool in said predetermined location; and drive means for selective actuation of said setting means for movement of said gripping means between said first and second positions thereof and of said seal expanding means. 3. The apparatus of Claims 1 or 2 wherein said support means comprise a plurality of lever means each of which is aligned longitudinally with said housing and spaced circumferentially thereabout in side-by-side relationship, each said lever means supporting thereon at least a respective one of said gripping means. 4. The apparatus of Claim 4 wherein adjacent ones of said lever means are oppositely aligned relative to opposite ends of said housing. 5. The apparatus of any preceding Claim wherein said setting means comprise first and second spaced apart rings disposed annularly about said housing with said lever means disposed there between, said rings being relatively moveable Cowards and away from one another in response to actuation of said drive means for moving said gripping means between said first and second positions thereof. 6. The apparatus of Claim 5 wherein said lever means supporting said first portion of said gripping means are pivotally connected at one end thereof to one of said first and second rings, and said lever means supporting said second portion of said gripping means are pivotally connected at one end thereof to the other of said first and second rings. 7. The apparatus of Claim 6 wherein the ends of said lever means opposite to said ends thereof pivotally connected to said first and second rings abut the other of said first and second rings in wedging relationship thereto, so that as said first and second rings move relatively towards one another, said ends of said lever means in wedging relation thereto are moved towards said inner surface until said gripping means are in said second position thereof. 8. The apparatus of any preceding Claim wherein, when said gripping means are in said second position thereof, said gripping means are wedged compressively into contact with said inner surface such that pressure acting on either end of said housing will maintain either or both of said first and second portions of said gripping means in said second position thereof. 9. The apparatus of Claim 5, 6, 7 or 8 wherein said lever means each comprise a link portion and a head portion pivotally connected to one end of said link portion, the other end of said link portion being pivotally connected to one of said first and second rings, said gripping means being removably connected to said head portion in opposed relationship to said inner surface. 10. The apparatus of Claim 9 wherein said head portion includes wedging surfaces adapted to cooperate with opposed wedging surfaces on the respective one of said first and second rings in abutting relationship thereto for movement of said head portion towards said inner wall as said first and second rings move relatively towards one another. 11. The apparatus of Claims 9 or 10 wherein each of said rings includes at least first and second contiguous wedging surfaces, said first wedging surface being at a relatively steep angle to the longitudinal axis of said housing for relatively rapid movement of said head portion towards said inner surface, and said second wedging surface being at a relatively shallow angle co said longitudinal axis and being adapted to compound the wedged compressive contact between said gripping means and said inner surface. 12. The apparatus of Claim any of Claims 3 to 11 including return means for positively returning said lever means into said first position thereof as said first and second rings move relatively away from one another. 13. The apparatus of any preceding Claim wherein said gripping means comprise replaceable pads of a deformable metal material relatively softer compared to the hardness of said inner surface and having therein a predetermined amount of granular material for improved frictional contact between said pads and said inner wall. 14. The apparatus of any of Claims 10 to 14 wherein the angle of said first wedging surface relative to said longitudinal axis is in the range of 60 degree  to 75 degree  and the angle of said second wedging surface relative to said longitudinal axis is in the range of 5 degree  to 15 degree . 15. The apparatus of Claim 3 wherein each of said levers supports adjacent one end thereof at least a respective one of said gripping means, such that with said levers in said second position thereof, said gripping means engage said inner wall in a staggered array. 16. The apparatus of any preceding Claim wherein said housing includes a fluid bypass formed therethrough, said bypass being selectively actuatable to allow fluid in said pipeline to flow through said housing for adjustment or equalization of said fluid pressure across said housing. 17. The apparatus of any of Claims 2 to 16 wherein said braking means are disposed between said at least first and second sealing members. 18. The apparatus of any or Claims 2 to 17 wherein said seal expanding means comprise at least first and second pairs of wedging rings disposed annularly about said tool with at least one of said sealing members being disposed between the wedging rings of each said pair thereof, the wedging rings of each said pair being relatively movable towards and away from one another in response 10 actuation of said drive means for expansion and contraction of said sealing members. 19. The apparatus of Claim 18 wherein said first ring and one of said wedging rings of said first pair thereof are the same component and wherein said second ring and one of said wedging rings of said second pair thereof are similarly the same component. 20. The apparatus of any preceding Claim wherein said drive means include a threaded driven member rotatable in the clockwise and counter-clockwise directions about its longitudinal axis, a prime mover operatively connected to said driven member for rotation thereof and means operatively associated with said driven member and threadedly connected thereto to move axially back and forth relative to said housing in response to clockwise and counter-clockwise rotation of said driven member, such that axial movement of said means in one direction actuates said sealing and braking means when said tool is to be held in said predetermined location and axial movement of said means in the opposite direction releases said sealing and braking means so that said tool is movable relative to said pipeline. 21. In a pipeline isolation tool for plugging a pipeline at a predetermined location, said tool including a housing adapted for movement through the pipeline, sealing means disposed annularly about said housing and being expandable into fluid sealing contact with the pipeline inner wall and braking means adapted to frictionally engage the inner pipeline wall to hold the tool in a predetermined location against the pressure of fluid in the pipeline, the improvement comprising an electro-mechanical drive system, said system comprising: a threaded driven member rotatable in the clockwise and counter-clockwise directions about its longitudinal axis; a prime mover operatively connected to said driven member for rotation thereof; and means operatively associated with said driven member and threadedly connected chereto to move axially back and forth relative to said housing in response to clockwise and counter-clockwise rotation of said driven member, such that axial movement of said mea